Method for building pneumatic tires in an improved tire mold

ABSTRACT

The invention relates to the manufacture of a tire ( 10 ) in a bladderless tire mold ( 12 ) that incorporates sealing rings ( 16, 18, 70 ) that enable the tire ( 10 ) to be easily and quickly installed within the tire mold ( 12 ) so that the pressurized gas or fluid used to inflate and vulcanize the tire ( 10 ) does not leak around the tire bead sections ( 44, 46 ) of the tire ( 10 ) and escape into the mold cavity ( 60 ). An improved method of mounting the tire ( 10 ) into the bladderless tire mold ( 12 ) allows the tire ( 10 ) to be quickly and easily loaded in and unload from the tire mold ( 12 ) without the need of moving any mold parts into or out of the space between the tire bead sections ( 44, 46 ).

RELATED APPLICATIONS

This application is related to International Application Ser. No.PCT/US97/04859 entitled PNEUMATIC TIRES WITH VULCANIZED INNERLINER ANDMETHOD FOR UTILIZING INNERLINER filed Mar. 25, 1997 and having a commonassignor with the present application.

1. Technical Field

The present invention relates to an improved tire mold construction andto an improved method of building tires that incorporates the advantagesachieved through the use of the new constructional design for the tiremold. More particularly, the present invention relates to an improvedmethod of building tires with a tire mold for shaping and curing oftires without a tire bladder.

2. Background of the Invention

To better understand the advantages and improvements achieved with thepresent invention, a brief discussion of tire construction and buildingprocedures follows. A pneumatic tire is typically constructed byapplying various components, or plies of the tire as flat stock, upon arotating tire building drum to form a hollow, toroidal shaped green oruncured tire. The order of applying the components is as follows: first,an innerliner is wrapped upon the tire building drum; the innerliner isfollowed by carcass plies containing tire reinforcement, the carcassplies are followed (not necessarily in the following order) by thebeads, apexes, chafers, side walls, belts and tread. The components arethen expanded and formed into a toroidal shaped, green tire assembly, ina manner well known in the art. The green tire assembly is then removedfrom the tire building drum and placed into a shaping and vulcanizingmold having the shape of the finished tire. The mold is sealed and thetoroidal shaped green tire assembly is heated and expanded radiallyoutward into the mold periphery by injecting pressurized gas or fluidinto a curing bladder mounted within the mold and disposed within thegreen tire assembly. As the curing bladder expands, it forces the treadand sidewalls of the green tire assembly into contact with the heatedmold walls to shape and vulcanize the green tire assembly into a fullyvulcanized tire. During the radial expansion of the green tire assemblywithin the shaping and vulcanizing mold, the toroidally shaped pliesexpand radially outward to dimensions slightly beyond those of theoriginal green tire assembly. Therefore, the bladder is conventionallymade of an expandable elastomeric material, usually butyl rubber, forresistance to steam.

During the production of tires on an assembly line, the curing bladderwithin the shaping and vulcanizing mold periodically wears out or fails.This has proven to be a difficult problem to overcome because of theharsh environment and demanding operating conditions to which theelastomeric bladder is subjected, being part of an assembly line that isoperating around the clock and throughout the year. For example, thebladder is located in a heated mold and is constantly being expanded andcontracted for each tire built. Moreover, the bladder is being subjectedto high temperature, pressurized gas or fluid, such as steam, which isused to expand the bladder.

The high paced manufacturing methods of building tires on an assemblyline is limited by the time required to shape and vulcanize each greentire in the tire molds. The tire molds are very expensive and typicallyseveral tire molds are provided for each tire building drum. Still, theprimary cause for downtime of the assembly line is the need to replace adefective or worn bladder in a tire mold. This fact, combined with theexpense of purchasing and maintaining each of the tire molds, results ina concentrated effort by the tire industry to keep the tire moldsoperational. This effort is very expensive given the reduced tireproduction during the significant downtime that a tire mold is notoperational, the labor cost for installing a new curing bladder andputting the tire mold back into operation, and the cost of manufacturingor purchasing the bladders themselves.

The tire industry has tried to eliminate the need for a curing bladderused in tire production. For example, U.S. Pat. No. 3,143,449 ('449)discloses a bladderless tire mold for curing and shaping a green tire.The green tire has an unvulcanized, barrel shaped, spliceless innerlinerfor completely sealing the inside of a green tire against the escape ofpressurized fluid into the tire body during the vulcanizing operation ina tire vulcanizing mold. The '449 patent discloses that by eliminatingthe splice in the tire innerliner, the inflation fluid in a bladderlessmold was unable to escape through the splice into the body of a greentire being molded and vulcanized in a tire vulcanizing mold. However,the mounting of the green tire into the mold requires a complicated moldconstruction that permitted the injection of inflation fluid into thetire body being molded in the bladderless mold to the desired shape.

Also pertinent to the present invention, there was disclosed in U.S.Pat. No. 4,166,883 ('883) a bladderless mold for curing tires. A beadsealing ring is inserted between the beads of the tire before the tiremold is closed, and serves as a gasket. The ring which is typically madeof steel or other hard elastomeric material can include extension thatare pressed inwardly by the tire as the tire mold is closed to shape thebead and form a tight seal, as illustrated in FIG. 7 of the '883 patent.The sealing ring is typically made of steel or other hard material whichis flexible to the extent that it can press inwardly upon the tire toshape the bead and form a tight seal when the tire mold is closed. Theproblem with this tire mold construction is the degree of mechanicalcomplexity required to insert the sealing ring between the beads of thetire after the green tire has been placed within the tire mold butbefore it is closed. Another significant design consideration relatingto the sealing ring of the '833 patent is that the extension permitdeflection of the outer surface of the member 29 from the position shownin dotted lines, to that shown in full lines, see FIG. 7 and thediscussion on column 5 lines 13 through 18 of the '833 patent.Fundamentally, while the '883 patent has removed the bladder from themold, it still requires a rather complicated mechanism for sealing thetire during the shaping and vulcanization which increases the complexityand limits the speed of the tire mold operation.

U.S. Pat. No. 4,181,483 shows an apparatus for the bellowlessvulcanization of tire blanks including an elastomeric ring to sealagainst the tire bead.

Another design, as shown in U.S. Pat. No. 1,982,674 ('674), is theprovision of a sealing ring with flexible side members that seal againstthe bead portions of the tire to prevent the escape of the pressurizedgas or fluid. As with the '883 patent, the construction of the sealingring disclosed in the '674 patent is cumbersome because it is mountedinto the green tire prior to the placement of the green tire and sealingring assembly into the tire mold. This assembly procedure is laborintensive and not suitable for modern, automated assembly linetechniques. Also, the side members are an integral part of a rathercomplex sealing ring, as seen in FIG. 3, which is more prone to failurebecause of the harsh environment in which it is operated.

It is apparent that there is still a need to provide novel bladderlesstire mold constructions and methods of operation for manufacturing tireson high speed assembly lines that reduce: a) the time and/or labor costsfor mounting a green tire in a shaping and vulcanization mold; b) thedowntime when a tire mold is not operational; and c) the labor andmaterial cost for installing a new curing bladder and putting the tiremold back into operation.

OBJECTS AND SUMMARY OF THE INVENTION

It is an object of the present invention to provide a bladderless tiremold construction and method of inserting a green tire and removing avulcanized tire from the tire mold being as defined in one or more ofthe appended claims and, as such, having the capability of beingconstructed to accomplish one or more of the following subsidiaryobjects.

It is yet a further object of the present invention to provide animproved method of shaping and vulcanizing tires which includes sealingrings that enable a tire to be easily and quickly installed within thetire so that the pressurized fluid used to inflate the green tire doesnot leak around the bead portions of the tire and escape into the tiremold cavity.

It is still another object of the present invention to provide abladderless method of tire construction wherein the sealing rings, usedto prevent the leakage of pressurized fluid from the interior of thegreen tire to the space between the tire and the walls of the tire moldcavity, are relatively inexpensive to manufacture and install.

It is yet another object of the invention to provide a method ofmounting a green tire into a shaping and vulcanization tire mold whereinthe tire can be simply inserted from the top of an open tire mold andthen withdrawn in the opposite direction without the need of moving anytire mold parts into or out of the opening between the tire beads.

In accordance with the invention, there is disclosed an improved tiremold having first and second tire mold sections each having first andsecond bead support sections forming a mold cavity. The first and secondbead support sections are spaced from each other when the first andsecond mold sections are sealed to provide a central opening into themold cavity. First and second clamp rings project into the centralopening through the first and second mold sections. First and secondseal rings are secured at one end to the first and second clamp rings,respectively, for sealing the bead ring sections of a tire against thefirst and second bead support sections.

Also in a accordance with the invention, the first and second seal ringsare annular shaped, flexible members each having a one annular end,forming the inner peripheral portion of the seal ring, which can bethinner than the opposite annular end forming the outer peripheralportion of the seal ring which is clamped to the clamp rings. The sealrings also can have a tapered intermediate portion extending from thethicker inner peripheral portion to the thinner outer peripheralportion.

Further in accordance with the invention, there is provided an improvedmethod of manufacturing a tubeless, pneumatic tire using the improvedbladderless tire mold with sealing rings previously described. Themethod includes the following steps: First, the green tire with beadcontaining sections is loaded into an annular tire mold cavity formed offirst and second annular tire mold sections having annular bead supportsections adjacent a central opening through the first and second annulartire mold sections. The bead ring sections of the tire are pressedagainst the first and second annular bead support sections with firstand second seal rings secured to first and second seal clamp supportmembers projecting into the central opening through the first and secondtire mold sections. Then, the bead ring sections of the tire are sealedagainst the first and second annular bead support sections with thefirst and second seal rings by introducing pressurized gas or liquidthrough the central opening into the tire. Next, the green tire isinflated with the pressurized gas or liquid to force the tire assemblyagainst the tire mold wall to mold and vulcanize the green tireassembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary, side elevational, broken away cross sectionalview showing a green tire assembly after being initially inserted withinan open bladderless, tire mold incorporating the seal rings of thepresent invention;

FIG. 2 is a fragmentary, side elevational, broken away cross sectionalview showing a green tire assembly within an open bladderless, tire moldafter the lower seal ring has been moved into engagement with the beadsection of the green tire;

FIG. 2A is a view showing the seal ring with dotted lines in the normalposition;

FIG. 3 is a fragmentary, side elevational, broken away cross sectionalview showing a green tire assembly within a closed bladderless, tiremold incorporating the seal rings of the present invention prior to theintroduction of pressurized gas to shape and vulcanize the tire;

FIG. 4 is a fragmentary, side elevational, broken away cross sectionalview showing a green tire assembly within a closed bladderless, tiremold incorporating the seal rings of the present invention after thepressurized gas has shaped and vulcanized the tire;

FIG. 5 is a fragmentary, side elevational, broken away cross sectionalview showing the upper seal ring being bent under as the tire beadsection of the green tire is forced over the seal ring during themounting of the green tire into the tire mold;

FIG. 6 is a fragmentary, side elevational, broken away cross sectionalview showing the lower seal ring being bent under as the lower tire beadsection of the green tire is forced over the seal ring during theremoval of the completed vulcanized tire from the tire mold;

FIG. 7 is a top view of the seal ring of the present invention; and

FIG. 8 is a cross sectional view of an alternative embodiment of a sealring having an embedded metal support ring.

DETAILED DESCRIPTION OF THE INVENTION

To best illustrate the present invention, FIG. 1 shows a green tireassembly 10 after being initially inserted within an open bladderless,tire mold 12 incorporating the seal ring assembly 14 of the presentinvention. An important aspect of the invention is that tire mold 12, asshown in FIG. 1, does not require the use of a curing bladder to shapethe tire assembly 10. The tire mold 12, except for the seal ringassembly 14 including but not limited to the sealing rings 16 and 18 andthe mounting structure 20 for the sealing rings, is constructed in anyconventional manner and does not form a part of the present invention.

MOLD CONSTRUCTION

The tire mold 12 is shown with a first tire mold section 22 and a secondmatching tire mold section 24. While the tire mold 12 is illustratedwith the first tire mold section 22 directly above and being the uppertire mold section as compared with the lower, second matching tire moldsection 24, it is within the terms of the present invention to orientthe tire mold sections in any other convenient orientation as long as agreen tire assembly can be loaded into the tire mold and a shaped,vulcanized tire can be withdrawn from the tire mold.

The present invention is directed to the seal ring assembly 14, bothstructurally and the method by which it enables improved tiremanufacturing processes including faster processing speed, improved tirequality, reduced tire mold complexity, reduced tire mold downtime, andreduced labor cost in tire mold maintenance. The seal ring assembly 14includes the sealing rings 16 and 18, the mounting structure 20 formounting the sealing rings, and any equivalent structure that performsthe function of the seal ring assembly as defined herein. A centermechanism 26 which moves longitudinally in either direction along thecenter axis 28 carries two support arms 30 and 32. While both arms 30and 32 are illustrated as being mounted to center mechanism 26 so thatthe arms move together, it is within the terms of the invention to mountthe arms to that they move independent of each other. One end 30 a and32 a of the support arms 30 and 32, respectively, are secured to centermechanism 26. The opposite ends 30 b and 32 b have clamp rings 34 and36, respectively, extending therefrom for securing the seal rings 16 and18, respectively. Note that the clamp rings 34 and 36 have a clamp baseportion 34 a and 36 a, respectively, integrally attached to the supportarms 30 and 32, and a removable seal attachment portion 34 b and 36 b,respectively, secured by conventional means, such as threaded screws 38.The seal attachment portions 34 b and 36 b have mating surfaces 34 c and36 c, respectively, that abut against corresponding mating surfaces 40 aand 42 a (see FIG. 1) of the conventional mold rings or bead rings 40and 42, which in turn are secured to the upper and lower tire moldsections 22 and 24, respectively.

The seal rings 16 and 18 are substantially identical and preferablyconstructed of a flexible, elastomeric material such as butyl rubber.The seal rings 16 and 18 typically have a washer like shape, asgenerally shown in FIG. 7 where only seal ring 16 is illustrated, with athicker end 16 a and 18 a, respectively, shaped to be securely attachedbetween the clamp base portions 34 a and 36 a and the removable sealattachment portions 34 b and 36 b, respectively. The opposite free ends16 b and 18 b of seal rings 16 and 18, respectively, are illustrated asbeing considerably thinner then the attachment ends 16 a and 18 arespectively. However, the thickness of the seal rings 16 and 18 can beconstant or even thicker at the outer ends 16 b and 18 b than theintermediate section therebetween. Note that the thickness of the sealrings 16 and 18 effect the time needed to cure the bead sections 44 and46 of the tire. After the seal rings 16 and 18 are abutted against thebead portions 44 and 46, respectively, of the tire, curing fluid caneasily force the seal rings against the inner surface of the tireassembly, as discussed in more detail below. Between the ends 16 a, 18 aand 16 b, 18 b of the seal rings 16 and 18, respectively, the seal rings16 and 18 are formed with curved outwardly facing surfaces 16 c and 18c. The radius of curvature of surfaces 16 c and 18 c for the seal rings16 and 18, respectively, is generally determined so that the curvedsurfaces 16 c and 18 c are located in the mold area including the beadsections of the tire, as illustrated in dotted lines on FIG. 2A. Theseal rings 16 and 18 can easily mold against the inner curved surface ofthe bead sections 44 and 46, respectively, of the tire assembly 10. Thecurved shape of the seal rings 16 and 18 creates a natural mechanicalbias of the elastomeric material, i.e., it is moved away from itsnatural location by the insertion of the bead ring sections of the greentire against the bead rings 42 and 44 and the seals 16 and 18. Then, thepressure exerted by the vulcanizing fluid pressing the seal rings 16 and18 against the inner curved surface of the bead sections 44 and 46 ofthe tire assembly 10, form an effective seal to prevent the leakage ofthe vulcanizing fluid therebetween.

METHOD OF OPERATION

The process begins with the tire mold 12 open, i.e. the upper tire moldsection 22 spaced away from the lower tire mold section 24, and thecenter mechanism 26 positioned so that the lower seal 18 is spaced awayfrom the bead ring 42. The green tire assembly 10, including a tirecarcass 50 with a tread portion 52 disposed thereabout, an uncured,partially cured or completely cured innerliner 54 aligned and securedwithin the tire carcass, and two tire beads 56 and 58 that are locatedwithin the tire bead sections 44 and 46, respectively, is loadeddownwards into the lower tire mold section 24. The ease and speed withwhich the tire assembly 10 can be loaded and unloaded from the tire moldis an important aspect of the present invention and a direct result ofthe improved seal ring assembly 14.

During the initial movement of the tire assembly 10 into the lower tiremold section 24, the tire bead section 46 (the first tire bead sectionto be introduced into the then open tire mold) is forced across the sealring 16 causing the seal ring to bend downward, stretching the seal ringsurface 16 c out of the way of the tire bead section 46, as shown inFIG. 5. As the tire bead section 46 continues to move downward towardsthe lower tire mold section 24, the bead section 46 forces the seal ring18 to bend downwards (not to the extent that seal ring 16 was bentbackwards), because the natural curvature of surface 18 c allows it tomore easily fold over on itself. This stretching is accomplished withsome ease because of the flexibility of the seal ring 16.

The ability of the seal rings 16 and 18 to bend in the oppositedirection from their natural curvature is an important aspect of theinvention in that it permits the tire assembly to be both loaded andunloaded extremely quickly and without the need (as required by theprior art bladderless tire molds) for any complicated mechanism orprocedure to insert a seal mechanism into the green tire assembly toprevent the forming and vulcanizing pressurized media, like steam, fromleaking into the tire mold cavity 60 between the tire assembly and theinterior tire mold wall.

The process of loading the tire assembly 10 into tire mold 12 continues,as shown in FIG. 2, when the center mechanism 26 moves downward in thedirection of the central axis 28. During the process step illustrated inFIG. 2, the clamp ring 36 seats against the bead ring 42 so that theseal ring 18 presses against the innerliner 54 of the tire assembly 10.Note that the end 18 b of seal ring 18 is disposed at a location inwardfrom the tire bead 58 towards the tire tread 52. Because of its naturalcurvature, the seal ring 18 forms a mechanical seal with the innersurface 62 (inner liner 54) of tire assembly 10. When the tire beadportion 46 is abutted against the bead ring 42, the tire bead portion 44of the tire assembly 10 is located above and in spaced relation to theseal ring 16.

Referring now to FIG. 3, the upper tire mold section 22 is next loweredinto sealing engagement with the lower tire mold section 24 to form thetire mold cavity 60 which encompasses the tire assembly 10. As the uppertire mold section 22 moves towards the lower tire mold section 24, thebead ring 40 engages the tire bead portion 44 containing the tire bead56 and moves the tire bead portion downward until the bead ring 40 isabutted against the clamp ring 34. The seal ring 16 then forms amechanical seal against the inner surface 62, i.e. inner liner 54, ofthe tire assembly 10 in the same way as described with regard to theseal ring 18.

Referring now to FIG. 4, the closed tire mold 12 with the tire assembly10 is illustrated with the pressurized curing and shaping fluid orliquid being directed through an inlet passageway 64 disposed betweenthe support arms 30 and 32. This pressurized fluid forces the tireassembly 10 against the tire mold walls. It can be understood that thefluid or liquid pressure, typically steam or hot gas pressure pressesthe seals 16 and 18 against the inner surface 62 of the tire beadsections 44 and 46 of the tire to effect a very strong seal thatprevents any leakage of the fluid or liquid into the tire mold cavity 60between the tire assembly 10 and the interior tire mold surface.

After the green tire assembly 10 has been shaped and vulcanized, thecuring and shaping fluid is exhausted through an outlet port (not shown)typically located between the support arms 30 and 32. Then, the uppermold section 22 is moved upward and out of the way. Again, the centermechanism 26 is moved along central axis 28 away from the lower tiremold section 24 so that the seal 18 is moved out of the engagement withthe bead ring portion 46 of the now cured tire. Nevertheless, as thecurved tire is removed from the tire mold by conventional means, theseal ring 18 is bent backwards as shown in FIG. 6, with the end 18 bbeing forced upwards so that the tire bead section 46 moves upward andcan move free from the seal ring 42 as the tire is removed from the tiremold 12. As the tire continues to move further out of the tire mold, thebead ring section 46 also crosses the upper seal ring 16. However,because of the flexibility of the seal ring 16, the bead ring section 46moves past the upper seal ring without much difficulty.

The ability of the seal rings 16 and 18 to operate in the harshenvironment of the heated tire mold, with the tires continually movingacross the seal rings, as they are loaded and unloaded from the tiremold, is a significant feature of the present invention. That is, thatthe seal rings 16 and 18 are flexible enough to enable the tire to besimply and quickly inserted downward into the tire mold and then removedfrom the tire mold without requiring any adjustment in the location ofthe seal rings except for a small amount of vertical movement which iseasily handled by the center mechanism 26. Further, when the seal rings16 and 18 are worn out by the constant flexure from moving the bead ringportions 44 and 46 of the tire assembly 10 across the seal rings, thedowntime to replace them is minimal because the seal rings are flexibleand easily removed and replaced between the clamp rings 34 and 36 andthe support arms 30 and 32, respectively, as discussed hereinbefore.

ALTERNATIVE EMBODIMENT

While the seal rings 16 and 18 are effective to seal against the beadsections of the tire, it is also within the terms of the invention tomold a washer shaped, metal insert 72 within the seal ring 70, asillustrated in FIG. 8. The metal insert 72 provides additional strengthfor the thinner sections of the otherwise elastomeric seal rings.

The seal ring 70 can be generally constructed in accordance with theprinciples discussed above with respect to seal rings 16 and 18, i.e.,of the same material and shape except for the embedded insert 72. Themodified seal ring 70 can replace the seal rings 16 and 18, as desired.The embedded metal washer 72 can be formed of a flexible metal, such asspring steel, that enables the seal ring 70 to bend so that the beadsections of the tire assembly can move across the seal ring 70 in themanner described herein before. The metal insert 72 provides anincreased bias of the seal ring 70 during the initial contact with theinner surface of the tire bead portions to prevent the pressurizedshaping and vulcanizing media, i.e. the steam, from leaking between theseal ring 70 and the inner surface of the tire assembly during theinitial injection of the pressurized media into the tire assembly. Whilethe metal insert 72 is illustrated as extending from one end 70 a of theseal ring to a location near the opposite end 70 b of the seal ring, itis also within the terms of the invention to lengthen or shorten theinsert 72 to provide a balance of good sealing qualities with theflexibility needed to move as the bead sections of the tire assemblycross the seal ring.

It is apparent that there has been provided in accordance with thisinvention a bladderless tire mold and method of operating the tire moldthat satisfy the objects, means and advantages set forth hereinbefore.According to the invention, a bladderless tire mold includes sealingrings that enable a tire to be easily and quickly installed within thetire mold so that the pressurized gas or fluid used to inflate andvulcanize a green tire assembly does not leak around the bead portionsof the tire and escape into the mold cavity. A method of mounting agreen tire into the bladderless tire mold allows the tire to be quicklyand easily loaded in and unloaded from the mold without the need ofmoving any mold parts into or out of the space between the tire beads.

While the invention has been described in combination with embodimentsthereof, it is evident that many alternatives, modifications, andvariations will be apparent to those skilled in the art in light of theforegoing teachings. Accordingly, the invention is intended to embraceall such alternatives, modifications and variations as fall within thespirit and scope of the appended claims.

What is claimed is:
 1. A method of manufacturing a pneumatic tire in atire mold having upper and lower mold sections forming a mold cavity,each of the upper and lower mold sections having upper and lower moldrings adjacent an opening into the mold cavity, the method including:providing a seal ring assembly including first and second clamp ringsprojecting into the mold cavity opening and having first and secondelastomeric seal rings secured to the first and second clamp rings,respectively, so that the free ends of the first and second elastomericseal rings extend into the mold cavity for sealing first and second tirebead sections of a tire assembly against the upper and lower mold rings,respectively; loading the tire assembly into the lower mold sectionwhile spaced away from the upper mold section by forcing the second tirebead section across the first and second elastomeric seal rings causingthe first and second elastomeric seal rings to bend downward, stretchingthe free ends of the first and second elastomeric seal rings out of theway of the second tire bead section until the second tire bead sectionis against lower mold ring; sealing the second tire bead section againstthe lower mold ring by abutting the second elastomeric seal ring againstthe second tire bead section; and lowering the upper mold section intosealing engagement with the lower mold section while the upper mold ringengages the first tire bead section and moves the first tire beadsection downward until the first elastomeric seal ring forms a sealagainst the first tire bead section.
 2. The method of manufacturing asset forth in claim 1 further characterized by: moving the upper moldsection upward and away from the lower mold section and moving thesecond elastomeric seal ring out of engagement with the second tire beadsection; removing the tire assembly from the tire mold so that thesecond elastomeric seal ring is bent backwards with the free end beingforced upwards so that the second tire bead section moves upward andfree from the lower mold ring as the tire assembly is removed from thetire mold; and moving the tire assembly further out of the tire moldcausing the first tire bead section to cross the first elastomeric sealring.
 3. The method of manufacturing as set forth in claim 2 furthercharacterized by: moving the upper and lower mold sections away from thefirst and second elastomeric seal rings to enable a next tire assemblyto be inserted downward into the tire mold and then removed from thetire mold without moving the first and second elastomeric seal ringsinto and out of the mold cavity.